if immigrants a month isnt an invasion they literally invade our country by illegally crossing our border and mexicos border invade enter a place situation or sphere of activity in large numbers especially with intrusive effect invasion an unwelcome intrusion into anothers domain an incursion by a large number of people or things into a place or sphere of activity stadium guards are preparing for another invasion of fans synonymsinflux inundation inrush rush flood torrent deluge stream avalanche every year the valley suffers an invasion of cars